1. Field of the Invention
The present invention relates to a novel method of forming a photographic image and more particularly, to a method of forming a photographic image consisting of metallic silver and a dye.
2. Description of the Prior Art
In the general method of forming a black-and-white photographic image, a silver halide photosensitive material is imagewise exposed to light to form a latent image therein, and is then development-processed with a developing solution containing a commonly used black-and-white developing agent (such as hydroquinones, aminophenols, 3-pyrazolidones, etc.) to produce metallic silver in the area where the latent image had been formed. Thus the silver is directly utilized as the black-and-white image, while the developing agent that has been oxidized in developing the silver is removed from the photographic system since it has already become useless.
However, if such an oxidized developing agent as described above is utilized to effect the formation of a dye with an imagewise distribution in the photosensitive material, attainable maximum density of the photographic image can be increased and consequently, the amount of silver required in forming the image can be reduced, since the density of the photographic image is the sum of both the density of the silver image and the density of the dye image.
Various methods have been reported for implementing such a system. For instance, U.S. Pat. No. 3,114,833 describes double-layer color X-ray sensitive materials, and U.S. Pat. No. 3,734,735 describes a method of forming a blue colored dye image that is coextensive (that is, formed in the same image areas) with the silver image, utilizing a cyan coupler.
However, cyan couplers such as those described in U.S. Pat. No. 3,734,735 often suffer from the defect that they tend to form unstable dyes.
Another such system is described in U.S. Pat. No. 4,126,461. However, it is difficult to attain satisfactorily high maximum density using the couplers of resorcinol derivatives as described in U.S. Pat. No. 4,126,461.